Rheological behavior of asphaltite-modified bituminous binders

This work focuses on the rheological properties of asphaltite-modified bituminous binders. The natural asphaltite, employed to modify a petroleum-derived-bitumen, is mined in Albania. At a first time, penetration,ring ball temperature and rheological properties of both asphaltite and pure petroleum bitumen are determined. Then, the petroleum bitumen is mixed with 5, 10 and 15% of natural bitumen and the penetration and ring ball temperature of the blends are assessed. In addition to this, rheological tests are performed on the 10% blend. The rheological experimental tests are carried out by means of a visco-analyzer METRAVIB under annular shearing and tension-compression loadings. Based on the experimental results and assuming that the material follows the time-temperature superposition principle (TTSP), master curves of complex modulus and of phase angle are constructed. The results show that the modified bitumens get stiffer and behave more elastically with the modification rate. This evolution is explained by the physicochemical composition of the asphaltite which presents high asphaltene agglomerates content. These improved characteristics are interesting for binders’ behavior at high temperature conditions in pavement applications. The experimental data are modeled by means of a simple blending law. In addition to this, some efforts are done to model the blend’s behavior by the Palierne’s model developed for emulsions of viscoelastic phases.